1. Field of the Invention
This invention generally relates to surface bonding on an indefinite or running length of flexible web and means for applying a separate web to a shaped web, and more particularly to a single-facer corrugating machine having self-adjusting web guides holding the corrugated web against the corrugating roll.
2. Description of the Prior Art
In the manufacturing of single-face corrugated paperboard, a web of paperboard material is fed from a roll of paperboard material and into a single-facer corrugating machine. Once in the corrugating machine the web of paperboard material is fed around a first corrugating roll having splined teeth running horizontally along the length thereof. A second corrugating roll also having splined teeth along the length thereof is parallel to and in meshing engagement with the splined teeth of the first corrugating roll. The web of material is fed through the nip between the intermeshing splined teeth of the first and second corrugating roll, causing the web of material to deform to the shape of the intermeshing splined teeth, thus forming the corrugations or flutes on the corrugated web. The corrugated web of material travels around the second corrugating roll and an adhesive roll parallel to and adjacent the second corrugating roll applies an adhesive to the tips of the flutes of the corrugated web. A pressure roll parallel to and adjacent the second corrugating roll carries a facing web from a roll of facing material and presses the facing web against the tips of the flutes having adhesive thereon, thus forming single-face corrugated paperboard. The single-faced web is used in forming packaging material or forming double face corrugated paperboard.
In the above operation for manufacturing single-face corrugated paper web the corrugated web must be held in close proximity to the second corrugating roll to prevent the corrugated web and consequently the flutes of the corrugated web from disengaging itself from the second corrugating roll. Should the corrugated web be allowed to become disengaged from the second corrugating roll, fluff out will occur causing blisters in the single-face web which must then be thrown away as scrap. Even with minor fluff out, malformed flutes are produced which reduces the quality of the corrugated paperboard being made. To prevent the corrugated web from becoming disengaged from the second corrugated roll industry has used a plurality of spaced manually adjustable stationary guides extending from approximately the nip between the first and second corrugating rolls and around the second corrugating roll to the nip between the second corrugating roll and the pressure roll. These fixed guides conventionally have a thin strip of metal having an arcuate shape substantially the same as the second corrugating roll in contact with the corrugated web. The thin metal strips are held stationary against the web by conventional rigid supports. These guides hold the corrugated web against the second corrugating roll as the corrugated web travels around the second corrugating roll prior to the web coming in contact with the web on the pressure roll.
The thin metal strips or guide fingers that hold the corrugated web in contact with the second corrugating roll are fixably held in place by means of rigid supports that are bolted to the machine structure members in proximity to the lower corrugating roll. Such rigid supports and guide finger arrangements are shown in Bucker U.S. Pat. No. 2,542,230, A. F. Shields, U.S. Pat. No. 2,711,206, and H. Meister, U.S. Pat. No. 3,346,436. As shown in the above prior art patents, the guide fingers are held stationary by the rigid supports, however, provisions are made to adjust the individual guide fingers, but once adjusted the guide fingers are stationary and nonmovable. Considerable skill is required to properly adjust the guide fingers and since there are a plurality of guide fingers stationed along and parallel to the second corrugating roll, each one of the guide fingers must be individually and manually adjusted to the correct position to insure that the corrugated web is held in close proximity to the second corrugating roll. The manual adjustment by the operator of each individual guide finger takes a considerable amount of time and due to the location of the guide fingers in the single facing machine it is extremely difficult for the operator to reach the adjusting mechanisms. In addition, the adjustment is made more difficult due to the close proximity of the steam heating rollers upon which the operator may be burned.
All the guide fingers must be individually adjusted properly because if the operator adjusts the guide fingers too loosely, fluff out can occur resulting in the disadvantages previously described. Should the operator adjust the guide fingers too tight against the corrugated web, guide finger marks will be formed on the flutes which results in a reduction of the corrugated boards strength. In addition, due to the movements of the machine elements and the heat related expansions and contractions of the various elements in the single-facing machine, the guide fingers will no longer be in proper adjustment because once they are adjusted by the operator they are held stationary and non-movable. Thus, the expansion or contraction of the machinery may cause the corrugated web either to become crushed by the guide fingers or creates poor quality corrugated board due to fluff out. In addition, splices made in the web material, web wrap-ups, or a change in web thickness will cause an increase in web thickness between the guide fingers and the second corrugating roll which may force the guide fingers out of adjustment or in extreme cases will even bend the guides or the second corrugating roll. In the prior art devices, there is provided no means to combine a close guide finger setting and at the same time provide for additional paper accumulation between the guide fingers and the second corrugating roll.